(a) Field of the Invention
The present invention relates to a micro lens panel unit for a three-dimensional display device, a three-dimensional display device, and a manufacturing method thereof.
(b) Description of Related Art
Nowadays, services which will realize acceleration of information transport on the basis of the information superhighway are gradually being advanced. Examples include a service such as for telephones for simply listening and speaking, and a multimedia-type service for seeing and listening using a digital terminal unit processing characters, voice, and image at a high speed. Moreover, such services are expected to eventually advance toward a three-dimensional information communication service for watching, feeling, and enjoying, transcending time and space.
Generally, three-dimensional (3D) images are formed by a principle of stereo eyesight via two human eyes, i.e., a parallax of two eyes occurs since the two eyes exist at a distance of approximately 65 mm apart, and the parallax of two eyes is a main factor for 3D sensing. That is, two eyes look at two different two-dimensional (2D) images for transmittance to the brain via the retinas, and the brain synthesizes the two images with each other to reproduce depth and reality of the real image. Such capability is commonly called strereography.
A 3D image display device uses the parallax of two eyes, and is classified as a stereoscopic type and an auto-stereoscopic type depending on a type of glasses used. The stereoscopic type includes a polarizing type and a time-divisional type, and the auto-stereoscopic type includes a parallax-barrier type, a lenticular type, a micro lens type, and a blinking light type.
For the former, many people can enjoy the 3D image but separate polarizing glasses or glasses with a liquid crystal-shutter must be used, and for the latter, only a small number of people can enjoy the 3D image since the 3D display device is provided with equipment such as an image splitter, a micro lens corresponding to a cylindrical lens array, and a configuration combining a parallax-barrier, thereby fixing a viewing range, but the latter is preferable due to no need to use separate glasses. That is, the stereoscopic 3D image display device forces users to put on glasses and thus they have trouble in viewing. On the contrary, an auto-stereoscopic 3D image display device allows users to enjoy 3D images by simply looking at them.
The auto-stereoscopic 3D image display device displays the 3D image by arranging a 3D image formation apparatus on a display panel. 3D image formation apparatuses include a micro lens and a parallax barrier. The 3D image formation apparatus may be provided with a conversion means using combination or addition in order to display 2D image as well as the 3D image. For example, addition of a switching unit and a micro lens having refracting anisotropy (referring to WO patent No. 03/015424-A2), or a combination of a switching unit and a retarder (referring to U.S. Pat. Nos. 6,046,849, 6,055,013, 6,437,915), or a combination of a switching unit and a polarizer provided with slits (referring to U.S. Pat. Nos. 4,717,949, 6,157,424) may make the 3D image formation apparatus that is capable of converting the 2D image and 3D image reciprocally.
3D image display devices using a micro lens have been widely developed in consideration of thickness and aperture of the display devices. That is, use of the micro lens causes the thickness of the display device to be thin and increases the aperture.
The 3D image display device using the micro lens typically includes a display panel, a micro lens panel, and a switching unit. The micro lens panel is the most important portion thereof, and as the micro lens panel is manufactured delicately, the 3D image display device display 3D image clearly.
However, the micro lens formed on the micro lens panel has many problems at the time of manufacture.
The micro lens is formed, after forming a frame having a shape of a concave lens using a resin on a substrate such as a glass, liquid crystal is injected into the shape of the concave lens, and then another substrate is attached to the substrate with the lenses and the liquid crystal sealed therebetween.
In this case, the frame with a concave lens shape made of the resin has pitches formed between the concave lens, but the pitches are not sharp but rather are smooth. The smooth pitches are a cause of deterioration of display quality for the 3D image.